sqeptiq is right, the postmodern idea that there are an infinite number of possible narratives while seemingly true is misleading.  It's true of abstract reality to some extent but there is an internal contradiction.  That contradiction arises out of the naturalistic heritage of postmodernism.  As far as physicists know nothing comes from nothing.  From the naturalistic perspective the universe is a complex chain of causes and effects which leads to the deterministic worldview that postmodernists apply when they want to argue against individual responsibility.  When they find something objectionable in society however they adopt a willful position.  The two positions are incompatible leading to cognitive dissonance.   There brains fry as sqeptiq puts it.

The problem that anyone arguing against the postmodernist position has is that there is no argument from the natural philosophy perspective that counters determinism.  So you get the popularist position  of "believe in science" as a counter to any argument that requires freewill.  Whatever the descendants of postmodernism propose must be right because from a naturalistic perspective it was predetermined.   It's why they feel free to make history conform to their ideology.  If historical data conflicts with their argument then something is wrong with the data not the ideology.  The ideology in their minds is "scientific".

Communists and socialists have a long history of "bad" science.  It turns out they are not very good natural philosophers.  Science relies on "genius" and genius should not be confused with intelligence.  High intelligence is a necessary but insufficient condition for genius.  Try and get a postmodernist to explain genius and they will stumble.  Another characteristic of genius besides high intelligence is imagination.  The apparent ability to create something from nothing.   While this ability of genius appears magical, that is something of an illusion.  Genius is dependent on many generations of evolved thinking tools and observations.  The postmodernist however never stops to think why something like religion evolved the way it did, why almost every successful civilization shares some moral prerogatives.  If they did consider the evolution of morality more carefully they would then be forced to question their own moral prerogatives and their evolution.  That is why they turn to power as the basis of social interaction.  

The problem with power as the basis for social organization is that successful civilizations are based more on voluntary cooperation than power.  From that arises another contradiction in postmodernism, who has the freewill to determine what form that cooperation takes from a deterministic perspective.  It turns out that they have no justification for being authoritarian but insist on social engineering that requires authoritarianism.   More cognitive dissonance is the result.  That is why you see the anti-fascists acting like fascists but their brains are so "fried" they do not have any consciousness of the contradictions in their actions.  As you would expect they do not have the imagination necessary for genius.  In fact they hate genius because it cannot be authoritarian.  

Communism and socialism claim to be scientific but at best it is very weak science.  It tries to apply science in its social engineering but lacking genius or imagination it almost always fails.  It turns out that the philosophical roots of communism are naturalism divorced from "good" science.  Science is just an excuse for doing "what comes naturally".  An excuse to tear down civilization that they find too restrictive.  An excuse for the immorality of natural behavior.

Postmodernism has fried their brains.